Add man page generation, change man section, update docs to reflect name change, and couple other tweaks

[jlinton]

Some distro's prefer man pages over .html or .rst files dumped into documentation directories. SPHINX can generate a man page from the existing documentation. So let's add a cmake rule to do it, and adjust the man section to 7.

Also, when reading the resulting documentation, there are a number of problems with it. Starting with the fact its out of date WRT to the hardware/etc requirements, build instructions, etc. Its also still calls itself "Hyperscan"

Let's do a quick pass to fix all the glaring errors.

[jlinton]

All these have been fixed IMHO. None of this is 100%, as there remains a number of hyperscan references that should be updated, but it is a bit of a rabbit hole for fixing the one thing I want to correct, which is the generation of the man pages.

I've also updated the pkgconfig to reflect it is no longer hyperscan despite keeping the hslib variable to maintain build compatibility with hyperscan users.

[jlinton]

Somehow, I appeared to have picked up the develop branch with differing commit IDs, which should now be fixed. However, I wonder if it was some kind of GitHub display glitch now. Either way, it looks right.